False Signals - Fisher CZ-7a PRO Quicksilver Operating Manual

FALSE SIGNALS

A "false signal" occurs when a target is incorrectly identified. For
example, a small broken-off piece of pull tab may be identified as
a nickel. Or a small deep coin, especially in mineralized soil, may
read "IRON." The more sensitive the metal detector, the harder it is
NOT to have false signals. Your CZ-7a Pro is an extremely sensitive
machine, so you're bound to encounter false signals. Here are
some of the most-frequent sources of false signals and what to do
about them:
1. Trash: The most common source of false signals.
Large or irregular pieces of trash may give positive,
lock-on false signals, In this case, you'll usually have
to dig the target, but with experience you'll be able
to eliminate many of the large targets whose size will
be obvious when you go into the pinpoint mode. In
the no-motion pinpoint mode, you'll be able to
judge the large dimensions of the object as you
pass the search coil over it.
Another false signal response may be a "one-way"
or disappearing signal. You'll sweep over the target
and get a good signal but you'll get nothing on the
return sweep. When this happens, you're over a
target that the CZ-7a Pro can't positively identify
due to its size, shape, depth or metallic composition.
For example, the CZ-7a Pro may I.D. a target as a
coin when swept in one direction and iron on the
return sweep. If your discrimination setting doesn't
reject coins or iron, you'll hear a high tone (for coin)
sweeping one way and a low tone (for iron) the
other way. Or if your discrimination setting rejects
iron, you'll hear a high tone sweeping in one
direction and nothing the other way.
Quite often the signal will just disappear and you
won't be able to find it no matter which direction
you sweep. These one-way and disappearing
signals are usually trash, and as a general rule you
should ignore them. If you have any doubts, press
the PINPOINT/SEARCH pad to get an accurate
location and then I.D. the target. If you still get a
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